string

MODULE

string

MODULE SUMMARY

String processing functions.

DESCRIPTION

This module provides functions for string processing.

EXPORTS

centre(String, Number) -> Centered
centre(String, Number, Character) -> Centered

Types:

String = Centered = string()

Number = integer() >= 0

Character = char()

Returns a string, where String is centered in the string and surrounded by blanks or Character. The resulting string has length Number.

chars(Character, Number) -> String
chars(Character, Number, Tail) -> String

Types:

Character = char()

Number = integer() >= 0

Tail = String = string()

Returns a string consisting of Number characters Character. Optionally, the string can end with string Tail.

chr(String, Character) -> Index

Types:

String = string()

Character = char()

Index = integer() >= 0

Returns the index of the first occurrence of Character in String. Returns 0 if Character does not occur.

concat(String1, String2) -> String3

Types:

String1 = String2 = String3 = string()

Concatenates String1 and String2 to form a new string String3, which is returned.

copies(String, Number) -> Copies

Types:

String = Copies = string()

Number = integer() >= 0

Returns a string containing String repeated Number times.

cspan(String, Chars) -> Length

Types:

String = Chars = string()

Length = integer() >= 0

Returns the length of the maximum initial segment of String, which consists entirely of characters not from Chars.

Example:

> string:cspan("\t    abcdef", " \t").
0

equal(String1, String2) -> boolean()

Types:

String1 = String2 = string()

Returns true if String1 and String2 are equal, otherwise false.

join(StringList, Separator) -> String

Types:

StringList = [string()]

Separator = String = string()

Returns a string with the elements of StringList separated by the string in Separator.

Example:

> join(["one", "two", "three"], ", ").
"one, two, three"

left(String, Number) -> Left
left(String, Number, Character) -> Left

Types:

String = Left = string()

Number = integer() >= 0

Character = char()

Returns String with the length adjusted in accordance with Number. The left margin is fixed. If length(String) < Number, then String is padded with blanks or Characters.

Example:

> string:left("Hello",10,$.).
"Hello....."

len(String) -> Length

Types:

String = string()

Length = integer() >= 0

Returns the number of characters in String.

rchr(String, Character) -> Index

Types:

String = string()

Character = char()

Index = integer() >= 0

Returns the index of the last occurrence of Character in String. Returns 0 if Character does not occur.

right(String, Number) -> Right
right(String, Number, Character) -> Right

Types:

String = Right = string()

Number = integer() >= 0

Character = char()

Returns String with the length adjusted in accordance with Number. The right margin is fixed. If the length of (String) < Number, then String is padded with blanks or Characters.

Example:

> string:right("Hello", 10, $.).
".....Hello"

rstr(String, SubString) -> Index

Types:

String = SubString = string()

Index = integer() >= 0

Returns the position where the last occurrence of SubString begins in String. Returns 0 if SubString does not exist in String.

Example:

> string:rstr(" Hello Hello World World ", "Hello World").
8

span(String, Chars) -> Length

Types:

String = Chars = string()

Length = integer() >= 0

Returns the length of the maximum initial segment of String, which consists entirely of characters from Chars.

Example:

> string:span("\t    abcdef", " \t").
5

str(String, SubString) -> Index

Types:

String = SubString = string()

Index = integer() >= 0

Returns the position where the first occurrence of SubString begins in String. Returns 0 if SubString does not exist in String.

Example:

> string:str(" Hello Hello World World ", "Hello World").
8

strip(String :: string()) -> string()
strip(String, Direction) -> Stripped
strip(String, Direction, Character) -> Stripped

Types:

String = Stripped = string()

Direction = left | right | both

Character = char()

Returns a string, where leading and/or trailing blanks or a number of Character have been removed. Direction, which can be left, right, or both, indicates from which direction blanks are to be removed. strip/1 is equivalent to strip(String, both).

Example:

> string:strip("...Hello.....", both, $.).
"Hello"

sub_string(String, Start) -> SubString
sub_string(String, Start, Stop) -> SubString

Types:

String = SubString = string()

Start = Stop = integer() >= 1

Returns a substring of String, starting at position Start to the end of the string, or to and including position Stop.

Example:

sub_string("Hello World", 4, 8).
"lo Wo"

substr(String, Start) -> SubString
substr(String, Start, Length) -> SubString

Types:

String = SubString = string()

Start = integer() >= 1

Length = integer() >= 0

Returns a substring of String, starting at position Start, and ending at the end of the string or at length Length.

Example:

> substr("Hello World", 4, 5).
"lo Wo"

sub_word(String, Number) -> Word
sub_word(String, Number, Character) -> Word

Types:

String = Word = string()

Number = integer()

Character = char()

Returns the word in position Number of String. Words are separated by blanks or Characters.

Example:

> string:sub_word(" Hello old boy !",3,$o).
"ld b"

to_float(String) -> {Float, Rest} | {error, Reason}

Types:

String = string()

Float = float()

Rest = string()

Reason = no_float | not_a_list

Argument String is expected to start with a valid text represented float (the digits are ASCII values). Remaining characters in the string after the float are returned in Rest.

Example:

> {F1,Fs} = string:to_float("1.0-1.0e-1"),
> {F2,[]} = string:to_float(Fs),
> F1+F2.
0.9
> string:to_float("3/2=1.5").
{error,no_float}
> string:to_float("-1.5eX").
{-1.5,"eX"}

to_integer(String) -> {Int, Rest} | {error, Reason}

Types:

String = string()

Int = integer()

Rest = string()

Reason = no_integer | not_a_list

Argument String is expected to start with a valid text represented integer (the digits are ASCII values). Remaining characters in the string after the integer are returned in Rest.

Example:

> {I1,Is} = string:to_integer("33+22"),
> {I2,[]} = string:to_integer(Is),
> I1-I2.
11
> string:to_integer("0.5").
{0,".5"}
> string:to_integer("x=2").
{error,no_integer}

to_lower(String) -> Result
to_lower(Char) -> CharResult
to_upper(String) -> Result
to_upper(Char) -> CharResult

Types:

String = Result = io_lib:latin1_string()

Char = CharResult = char()

The specified string or character is case-converted. Notice that the supported character set is ISO/IEC 8859-1 (also called Latin 1); all values outside this set are unchanged

tokens(String, SeparatorList) -> Tokens

Types:

String = SeparatorList = string()

Tokens = [Token :: nonempty_string()]

Returns a list of tokens in String, separated by the characters in SeparatorList.

Example:

> tokens("abc defxxghix jkl", "x ").
["abc", "def", "ghi", "jkl"]

Notice that, as shown in this example, two or more adjacent separator characters in String are treated as one. That is, there are no empty strings in the resulting list of tokens.

words(String) -> Count
words(String, Character) -> Count

Types:

String = string()

Character = char()

Count = integer() >= 1

Returns the number of words in String, separated by blanks or Character.

Example:

> words(" Hello old boy!", $o).
4

Notes

Some of the general string functions can seem to overlap each other. The reason is that this string package is the combination of two earlier packages and all functions of both packages have been retained.

Note

Any undocumented functions in string are not to be used.